High capacity electrochemically active materials are desirable for battery applications. However, these materials exhibit substantial volume changes during battery cycling, e.g. swelling during lithiation and contraction during delithiation. For example, silicon swells as much as 400% during lithiation to its theoretical capacity of about 4200 mAh/g or Li4.4Si. Volume changes of this magnitude cause pulverization of active materials structures, losses of electrical connections, and capacity fading.
Forming high capacity active materials into certain types of nanostructures can address some of these issues. Nanostructures have at least one nanoscale dimension, and swelling-contracting along this nano-dimension tends to be less destructive than along large dimensions. As such, nanostructures can remain substantially intact during battery cycling. However, integrating multiple nanostructures into a battery electrode layer that has adequate active material loadings is difficult. Such integration involves establishing and maintaining electrical interconnections and mechanical support over many cycles.